Tensile mechanofluorophoric polyurethane elastomers, [c2] daisy chain rotaxane tougheners and constituent compounds thereof

Abstract

A tensile mechanofluorophoric polyurethane elastomer is provided. The main chain structure of the polyurethane contains [c2] daisy chain rotaxanes as molecular artificial muscle tougheners. The [c2] daisy chain rotaxane is composed of two compounds, each having an axle portion with a macrocyclic moiety at one end and a stopper moiety at the other. The axle moiety of one compound penetrates the macrocyclic moiety of the other compound, and vice versa. The stopper moiety of the compound includes a mechanofluorophoric chromophore that is initially non-emissive. When the [c2] daisy chain rotaxane is incorporated into the main chain structure of polyurethane, the mechanofluorophoric chromophore emits light upon ring-opening induced by stretching force applied to the polyurethane. Additionally, if a fluorescent chromophore is attached to the macrocyclic moiety of the [c2] daisy chain rotaxane, ratiometric fluorescence behaviors with emission color switching properties can be achieved through the Förster resonance energy transfer (FRET) processes.

Description

Technical Field

[0001] This invention relates to a polyurethane elastomer containing [c2] pyrethroid as a molecular artificial muscle toughening agent, and more particularly to a stretch-type mechanically induced fluorescent polyurethane elastomer. Prior Technology

[0002] Artificial molecular machines composed of mechanically interlocked molecules (MIMs) possess specific mechanical bonds and reversible molecular switching behavior. Therefore, they can induce relative internal mechanical motion in response to external stimuli, thus exhibiting unique electronic, physical, and chemical properties. They have been extensively studied and applied in many related fields of supramolecular chemistry and materials science. In particular, mechanically interlocked polymers (MIPs), such as polyrotaxanes, polycatenanes, daisy chain polymers, and mechanically interlocked dendrimers, share the common characteristic of introducing mechanically interlocked structures into the polymer backbone to preserve the high degree of freedom and mobility of the component structure, including rotational, torsional, and sliding movements. Therefore, these mechanically interlocked polymers are considered to possess unprecedented properties, such as mechanical durability, flexibility, tensile strength, and reactivity, and hold promise for applications in many emerging fields.

[0003] [C2]daisy chain rotaxanes, a special type of MIM, comprises a molecular structure consisting of two "macrocycles plus a linear axle." The linear axle moiety of one molecule passes through the macrocycle moiety of the other molecule, and the linear axle moiety has at least two binding sites with the macrocycle. Therefore, the linear axle moiety can slide back and forth within the macrocycle moiety under different external stimuli. The ends of the linear axle moiety have large end caps to prevent the macrocycle moiety from detaching from the linear axle moiety, thus maintaining the stability of the molecular structure. Due to these properties, [C2]daisy chain rotaxanes have become a promising candidate for artificial molecular machines and are being integrated into advanced polymer materials. Summary of the Invention

[0004] One object of the present invention is to provide a compound comprising a plurality of moieties, which sequentially comprise a macrocyclic moiety, a first site moiety, a spool moiety, and a second site moiety. The macrocyclic moiety comprises a cyclic polyether moiety. The first site moiety is bonded to the macrocyclic moiety, wherein the first site moiety comprises a protonable dimethylene amino group, and when the first site moiety enters the macrocyclic moiety, a plurality of hydrogen bonds are formed between the first site moiety and the macrocyclic moiety. The spool moiety is bonded to the first site moiety and passes through the macrocyclic moiety. The second site moiety is bonded to the spool moiety, wherein the second site moiety comprises an ammonium group capable of forming an electronic resonance structure, and when the second site moiety enters the macrocyclic moiety, a plurality of hydrogen bonds are formed between the second site moiety and the macrocyclic moiety. A capping moiety is bonded to the second site moiety, wherein the capping moiety comprises a first chromophore.

[0005] According to one embodiment of the present invention, the macrocyclic moiety comprises the dibenzo-24-crown-8 moiety.

[0006] According to one embodiment of the present invention, the first chromophore comprises a rhodamine derivative portion (Formula II) or a tetraphenylethylene derivative portion (Formula III), wherein the rhodamine derivative portion is a mechanotropic chromophore. Formula II Formula III

[0007] According to one embodiment of the present invention, the macroring portion is further bonded with a second chromophore, wherein one of the first chromophore and the second chromophore can serve as an energy donor for Foster resonance energy transfer, and the other can serve as an energy acceptor.

[0008] According to one embodiment of the present invention, the first chromophore and the second chromophore each independently comprise a rhodamine derivative portion (Formula II) or a tetraphenylethylene derivative portion (Formula III), wherein the rhodamine derivative portion is a mechanotropic chromophore. Formula II Formula III

[0009] According to one embodiment of the present invention, the spool portion contains -(CH2)n-, n=6-16, some of which of the -(CH2)- can be -O- or Replace it.

[0010] According to one embodiment of the present invention, the chemical structural formula of the second site portion is as follows: , , , or .

[0011] According to an embodiment of the present invention, the large ring portion and the first station portion further include a first connection portion, the first connection portion including -(CH2)n-, n=0-9.

[0012] According to an embodiment of the present invention, the second station portion and the end cap portion further include a second connection portion, the second connection portion including -(CH2)nO-, n=1-10, wherein the -O- portion is connected to the end cap portion.

[0013] Another object of the present invention is to provide a [c2] pyrethroid toughening agent composed of two said compounds, wherein the spool portion of one said compound passes through the macrocycle portion of the other said compound, and vice versa.

[0014] According to an embodiment of the present invention, the above-mentioned [c2]pyrethroid toughening agent has one of the following chemical structural formulas: .

[0015] According to another objective of the present invention, a stretchable, mechanically induced fluorescent polyurethane elastomer is provided, the main chain structure of which comprises the above-mentioned [c2]pyrethroid rotaxane and a rhodamine derivative, having the chemical structural formula shown in Formula 3 below: .

[0016] According to an embodiment of the present invention, the monomer of the main chain structure further comprises: Tetraethylene glycol; and Hexamethylene diisocyanate.

[0017] According to one embodiment of the present invention, the monomer of the main chain structure further comprises a tetraphenylethylene derivative having the chemical structural formula shown in Formula 31 below: .

[0018] As can be seen from the above, introducing [c2]pyrethroid rotaxane, which has intramolecular sliding, switchable configuration and stimuli-responsive properties, into the mechanical fluorescent polyurethane (PU) framework can endow the material with excellent mechanical strength, high tensile strain, significant toughness and unique optical properties.

[0019] The foregoing summary is intended to provide a simplified overview of the invention, enabling the reader to gain a basic understanding. This summary is not a complete overview of the invention, nor is it intended to identify key elements of the embodiments or define the scope of the invention. Upon reading the following description of embodiments, those skilled in the art will readily understand the basic spirit and other objectives of the invention, as well as the technical means and implementation aspects employed. Simple Explanation of the Diagram

[0020] To make the above and other objects, features, advantages and embodiments of the present invention more apparent and understandable, the accompanying drawings are described below.

[0021] Figure 1A shows a cartoon structural diagram of the unfolded components of one constituent molecule in [c2] pyrifotaxane.

[0022] Figures 1B-1D show the chemical structural formulas and corresponding cartoon representations of [c2]pyrethroids DR / E, DR / C, DRT / E, DRT / C, DT / E, and DT / C, respectively.

[0023] Figure 2A shows the synthetic routes for [c2]pyrethroid rotaxanes DR / E and DR / C.

[0024] Figure 2B shows the synthetic routes of [c2]pyrethroid rotaxanes DRT / E and DRT / C.

[0025] Figure 2C shows the synthetic routes for [c2]pyrethroid rotaxanes DT / E and DT / C.

[0026] Figure 3 shows the chemical structure and synthetic route of the dirhodamine derivatives (compound 30 or compound R2).

[0027] Figure 4A shows the synthesis of PUR-DR polyurethane.

[0028] Figure 4B shows the synthesis of PUR-DT polyurethane.

[0029] Figure 4C shows the synthesis of PURT-DR polyurethane.

[0030] Figure 5 shows a schematic diagram of the luminescence of the rhodamine derivative monomer under stress, demonstrating its transformation from a non-luminescent closed-ring form to an open-ring form that emits yellow-orange light (i.e., the change of the PUR-6 film before and after stretching).

[0031] Figure 6 shows the relative photoluminescence (PL) intensity of the yellow-orange light emitted by the PUR-6 thin film under different strains.

[0032] Figure 7 shows the relative photoluminescence (PL) intensity of the yellow-orange light emitted by the PUR-DR / C-2 film under different strains.

[0033] Figure 8 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative portion emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative portion emitting yellow-orange fluorescence (λem = 575 nm) in the PUR-DRT / C-2 film under different strains.

[0034] Figure 9A shows the shape memory effect and luminescent color change of the PUR-DRT / C film during stretching and heating (approximately 100°C).

[0035] Figures 9B and 9C show the photoluminescence (PL) spectra and relative PL intensities of TPE (λem = 457 nm) emitting blue fluorescence and RH (λem = 575 nm) emitting yellow-orange fluorescence, respectively, in water at different temperatures (40, 55, 70, 85, and 100°C) after stretching to 5000% strain length.

[0036] Figure 10 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative portion emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative portion emitting yellow-orange fluorescence (λem = 575 nm) in the PUR-DT / C film under different strains.

[0037] Figure 11 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative portion emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative portion emitting yellow-orange fluorescence (λem = 575 nm) in the PURT-DR / C film under different strains. Implementation

[0038] This invention provides a stretchable, mechanically induced fluorescent polyurethane elastomer, the main chain of which comprises [C2] pyrethroid rotaxane with diol groups as a molecular artificial muscle toughening agent. The toughness of this stretchable, mechanically induced fluorescent polyurethane elastomer is enhanced by the mechanically interlocked [C2] pyrethroid rotaxane toughening agent. In the following description, exemplary structures of the above-described stretchable, mechanically induced fluorescent polyurethane elastomer and exemplary manufacturing methods will be described. [[c2]] [Molecular design of one of the constituent molecules of pyrethroid rotaxanes]

[0039] This study aims to design polyurethane (PU) elastomers based on [c2]daisy chain rotaxanes to develop advanced mechanofluorophoric materials. When [c2]daisy chain rotaxanes are used as molecular artificial molecular muscles, they exhibit both extended and contractile configurations. These configurations can be modulated by external stimuli (such as alkaline DBU (1,8-diazabicyclo[5.4.0]undec-7-ene) and acidic TFA (trifluoroacetic acid)) and mechanical forces, allowing for flexible adjustment of the material's mechanical and optical properties.

[0040] In the design, the [c2]pyrethroid rotaxane structure incorporates rhodamine (RH) or tetraphenylethylene (TPE)-based structures as bulky end-capping regions. Alternatively, when RH is chosen as the end-capping region, tetraphenylethylene (TPE) or its derivatives can be selectively introduced onto the macrocyclic region as energy donors exhibiting aggregation-induced emission (AIE) effects. After these [c2]pyrethroid rotaxane structures are embedded in the PU backbone, an elastomer material with significantly enhanced mechanical strength and optical physical properties can be formed.

[0041] Here, three structures of [c2]daisy chain rotaxanes, DR, DRT, and DT, were designed. In their names, D represents [c2]daisy chain rotaxanes, R represents rhodamine or its derivatives, and T represents tetraphenylethylene (TPE) or its derivatives. Furthermore, depending on whether the [c2]daisy chain rotaxane is in an extended or contracted form, it is indicated in the name with " / E" or " / C," respectively. Figure 1A shows a cartoon structural diagram of the unfolded components of a [c2]daisy chain rotaxane molecule. Figures 1B-1D show the chemical structural formulas and corresponding cartoon representations of [c2]daisy chain rotaxanes DR / E, DR / C, DRT / E, DRT / C, DT / E, and DT / C, respectively.

[0042] In Figure 1A, a component of [c2] pyrifotaxane consists of a macrocyclic portion 110, a first site portion 120, a spool portion 130, a second site portion 140, and a capping portion 150 from left to right.

[0043] The macrocyclic moiety (MC) 110 functions to form multiple hydrogen bonds with the first site moiety 120 or the second site moiety 140, thereby fixing the positively charged first site moiety 120 or second site moiety 140 within the ring space of the macrocyclic moiety 110. Therefore, the macrocyclic moiety 110 can achieve this purpose as long as it is a cyclic polyether derivative structure. In Figures 1B-1D, the macrocyclic moiety 110 of one constituent molecule of [c2]pyrethroid rotaxane is dibenzo-24-crown-8 as shown in Formula I below. [, ]DB24C8). Large ring portion: Formula I (DB24C8)

[0044] The stopper moiety (SP) 150 is used to prevent the macrocyclic portion 110 from detaching from the spool portion 130. Therefore, the area or volume of the stopper moiety 150 only needs to be larger than the intra-ring space of the macrocyclic portion. For example, in [c2] pyrethroid rotaxanes DR and DRT in Figures 1B, 1C-1, and 1C-2, the stopper moiety 150 is a rhodamine derivative portion (abbreviated as RH) as shown in Formula II below. In [c2] pyrethroid rotaxane DT in Figure 1D, the stopper moiety is divided into a tetraphenylethylene derivative portion (abbreviated as TPE) as shown in Formula III below. End capping portion: Formula II (RH) End capping portion: Formula III (TPE)

[0045] [c2]pyrethroid rotaxane has two station moiety (ST): a first station moiety 120 near the macrocyclic moiety 110 and a second station moiety 140 near the end-capped moiety 150. The first station moiety 120 is designed as a smaller dimethyleneamine group (in a basic environment) or a dimethyleneammonium group (in an acidic environment). In Figures 1B-1D, the first station moiety 120 of a constituent molecule of [c2]pyrethroid rotaxane is a dimethyleneammonium group or a dimethyleneammonium group, as shown in Formula IV. The second station moiety 140 is designed as a larger quaternary ammonium group. In Figures 1B-1D, the second station moiety 140 of a constituent molecule of [c2]pyrethroid rotaxane is an N-methyltriazolium (MTA) salt, as shown in Formula V. or First Station Section: Form IV Second station section: Type V (MTA)

[0046] Since the first site portion 120 of the two sites is a protonable dimethyleneamine group, the pH of the environment can be adjusted to control whether the first site portion 120 is located inside or outside the ring space of the macrocyclic portion 110. In an alkaline environment, when the first site portion 120 is a dimethyleneamine group, the [NH…O] hydrogen bonds formed between it and the multiple oxygen atoms of the macrocyclic portion 110 are weaker, making it more difficult for it to remain stably within the ring space of the macrocyclic portion 110. Conversely, in an acidic environment, when the first site portion 120 is a positively charged dimineammonium group, the multiple [⊕NH…O] hydrogen bonds formed between it and the multiple oxygen atoms of the macrocyclic portion 110 are stronger, allowing it to remain stably within the ring space of the macrocyclic portion 110.

[0047] The second site portion 140, due to its larger molecular volume and electronic resonance structure, has a lower charge density. Therefore, when the smaller first site portion 120 is positively charged in an acidic environment, its higher charge density causes it to preemptively remain within the ring space of the macrocyclic portion 110, allowing the second site portion 140 to leave. In weakly acidic or even slightly alkaline environments, the ammonium ions of the first site portion 120 dissociate, releasing some protons to form amino groups, resulting in weaker hydrogen bonds. This forces the second site portion 140 to remain within the ring space of the macrocyclic portion 110. Therefore, the second site portion 140 can be used with any ammonium group that can form a resonance structure, and is not limited to MTA. For example, it can also be used for... , , or These chemical groups all have resonance structures after the nitrogen atom is protonated to stabilize the positive charge after protonation.

[0048] In one of the constituent molecules of [c2] pyrethroid rotaxane, the linear axle moiety 130, which connects the first site moiety 120 and the second site moiety 140, is typically represented by a -(CH2)n- of appropriate length, some of which may be -O- or... Instead. According to some embodiments of the invention, n = 6-16, for example 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16. For example, in Figures 1B-1D, the axial portion 130 of one of the constituent molecules of [c2] pyrethroid rotaxanes DR, DRT and DT is -(CH2)-Ph-O-(CH2)10-.

[0049] In addition, a first connecting portion L1 may be included between the large loop portion 110 and the first station portion 120 to adjust the distance between the large loop portion 110 and the first station portion 120. The first connecting portion L1 includes -(CH2)n-, n=0-9.

[0050] The second station portion 140 and the end portion 150 also include a second connecting portion L2 to adjust the distance between the second station portion 140 and the end portion 150. The second connecting portion L2 includes -(CH2)nO-, n=1-10, wherein the -O- portion is connected to the end portion 150. [Experimental Example] [1-1] [:] [[c2]] [Pyrethroid rotaxane] [DR / E] [and] [DR / C] [The synthesis of]

[0051] Figure 2A shows the synthetic pathways for [c2]pyrethroid rotaxanes DR / E and DR / C. In Figure 2A, compound 14 (500 mg, 0.55 mmol) was first dissolved in degassed CHCl3 (30 mL) and stirred at room temperature for 3 hours to generate compound 15. Subsequently, compound 4 (390 mg, 0.83 mmol) and Cu[(CH3CN)4PF6] (310 mg, 0.83 mmol) were added to the solution of compound 15, and the mixture was stirred overnight at room temperature under nitrogen. The reaction mixture was diluted with DCM (30 mL), and then stirred with 0.1 M Na2EDTA aqueous solution (50 mL), followed by washing with NH4PF6 aqueous solution (2 × 20 mL) and water. The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by column chromatography (using DCM:MeOH = 50:1) to give compound 16 as a pale yellow solid (460 mg, 60.6%).

[0052] 1H NMR (400 MHz, acetone-d6, δ ppm): 8.07 (s, 2H); 7.85-7.82 (m, 2H); 7.61-7.55 (m, 4H); 7.53-7.51 (m, 4H); 7.34-7.25 (m, 4H); 7.05-7.00 (m, 8H); 6.98-6.91 (m, 6H); 6.89-6.79 (m, 6H); 6.68 (dd, J = 8.4 Hz, J = 2.4 Hz, 2H); 6.63 (d, J = 8 Hz, 2H); 6.59 (d, J = 8.8 Hz, 2H); 6.45 (s, 6H); 5.23 (s, 4H); 4.81-4.67 (m, 8H); 4.52-4.38 (m, 8H); 4.30-4.07 (m, 12H); 4.03-3.82 (m, 24H); 3.79-3.53 (m, 12H); 3.41 (q, J = 7.2 Hz, 8H); 3.28-3.23 (m, 4H); 3.21-3.15 (m, 4H); 1.94-1.87 (m, 4H); 1.79-1.71 (m, 4H); 1.46-1.41 (m, 4H); 1.33-1.29 (m, 20H); 1.16 (t, J = 7.2 Hz, 12H).

[0053] 13C NMR (125 MHz, acetone-d6, δ ppm): 168.32, 159.94, 159.64, 153.81, 153.00, 152.97, 149.13, 148.11, 146.71, 146.49, 142.97, 132.82, 130.80, 129.00, 128.53, 124.99, 124.34, 123.94, 123.72, 122.97, 122.65, 121.31, 120.94, 120.89, 114.88, 114.83, 113.70, 112.56, 112.33, 112.17, 111.99, 111.91, 108.76, 104.75, 101.80, 97.53, 71.83, 71.68, 71.34, 70.84, 70.68, 70.60, 70.54, 70.38, 70.02, 69.89, 69.53, 67.99, 67.89, 67.59, 67.48, 67.31, 64.70, 61.89, 60.00, 52.26, 51.86, 49.85, 44.07, 43.22, 30.14, 29.81, 29.62, 26.24, 25.84, 12.01.

[0054] HRMS (ESI+) [M-2PF6-]2+: calcd. for C142H178N12O262+, 1234.1499; found, 1234.1517.

[0055] Then, compound 16 (500 mg, 0.181 mmol) was dissolved in acetonitrile (MeCN, 10 mL), and iodomethane (CH3I, 10 mL) was added to the solution in a sealed tube, and the mixture was stirred at 45°C for 2 days. After the reaction mixture cooled to room temperature, excess acetonitrile and iodomethane were removed by vacuum evaporation. The resulting solid was washed several times with diethyl ether (Et2O), then suspended in acetone (30 mL), and excess saturated NH4PF6 solution was added, and the mixture was stirred overnight at room temperature. After removing the reaction solvent, the solid residue was added to deionized water (50 mL), filtered, and washed with water (3 × 50 mL). The resulting precipitate was then continuously washed with diethyl ether and dried in a vacuum oven for 12 hours to finally obtain the target [c2]pyrethroid rotaxane DR / E as a yellow solid (420 mg, 75.3%).

[0056] 1H NMR (500 MHz, acetone-d6, δ ppm): 8.95 (s, 1H); 8.93 (s, 1H); 7.83-7.81 (m, 2H); 7.59- 7.53 (m, 8H); 7.26-7.21 (m, 4H); 7.13-7.08 (m, 4H); 7.05-6.98 (m, 8H); 6.97-6.94 (m, 4H); 6.92-6.82 (m, 6H); 6.78-6.73 (m, 4H); 6.64 (d, J = 9.0 Hz, 1H); 6.60 (d, J = 8.0 Hz, 1H); 6.43 (s, 2H); 6.40-6.35 (m, 2H); 5.62 (s, 2H); 5.61 (s, 2H); 4.78-4.73 (m, 8H); 4.70-4.63 (m, 4H); 4.50 (s, 3H); 4.49 (s, 3H); 4.45-4.39 (m, 4H); 4.29- 4.21 (m, 6H); 4.17-4.04 (m, 8H); 4.00-3.94 (m, 8H); 3.90-3.81 (m, 8H); 3.79-3.70 (m, 8H); 3.67-3.48 (m, 10H); 3.38 (q, J = 7.0 Hz, 8H); 3.30-3.13 (m, 8H); 1.76-1.69 (m, 4H); 1.45-1.38 (m, 8H); 1.34-1.25 (m, 20H); 1.12 (t, J = 7.0 Hz, 12H).

[0057] 13C NMR (125 MHz, acetone-d6, δ ppm): 168.28, 159.96, 158.84, 158.32, 153.06, 152.85, 152.81, 152.18, 149.19, 148.15, 148.13, 146.73, 146.50, 142.37, 139.89, 139.68, 133.39, 132.87, 131.02, 130.81, 130.69, 129.94, 129.88, 129.60, 129.49, 129.37, 128.63, 128.57, 124.94, 123.82, 123.69, 123.12, 122.99, 122.71, 120.98, 120.92, 120.87, 117.37, 114.86, 114.80, 113.67, 112.72, 112.56, 112.33, 112.17, 111.95, 111.57, 108.92, 102.49, 102.21, 97.42, 70.59, 70.54, 69.87, 67.92, 67.48, 64.67, 64.64, 58.68, 58.61, 54.09, 46.07, 44.08, 43.41, 38.36, 29.80, 29.71, 25.91, 25.84.

[0058] HRMS (ESI+) [M-4PF6-]4+: calcd. for C144H184N12O264+, 624.5864; found, 624.5854.

[0059] [c2]Kyrizocarpine DR / E has a diemine ammonium group located in the inner ring space of the first station portion near the macrocycle. After obtaining the target [c2]Kyrizocarpine DR / E, the base DBU can be added to deprotonate the diemine ammonium group in the first station portion, replacing it with MTA from the second station portion, which enters the inner ring space of the macrocycle, forming the configuration of [c2]Kyrizocarpine DR / C. Conversely, if the acid TFA is added to [c2]Kyrizocarpine DR / C, the configuration of [c2]Kyrizocarpine DR / C can be restored to that of [c2]Kyrizocarpine DR / E. [Experimental Example] [1-2] [:] [[c2]] [Pyrethroid rotaxane] [DRT / E] [and] [DRT / C] [The synthesis of]

[0060] Figure 2B shows the synthetic pathways for [c2]pyrethroid rotaxanes DRT / E and DRT / C. In Figure 2B, compound 22 (500 mg, 0.39 mmol) was first dissolved in degassed CHCl3 (30 mL) and stirred at room temperature for 3 hours to generate compound 23. Subsequently, compound 4 (280 mg, 0.6 mmol) and Cu[(CH3CN)4PF6] (225 mg, 0.6 mmol) were added directly to the reaction mixture, and the mixture was stirred overnight at room temperature under nitrogen. The reaction mixture was diluted with DCM (30 mL), and then stirred with 0.1 M Na2EDTA aqueous solution (50 mL), followed by washing with NH4PF6 aqueous solution (2 × 20 mL) and water. The organic layer was collected, dried over anhydrous Na2SO4, and concentrated under reduced pressure. The crude product was purified by column chromatography (using solvent DCM:MeOH = 50:1) to give compound 24 as a yellow solid (450 mg, 65.8%).

[0061] 1H NMR (400 MHz, acetone-d6, δ ppm): 8.06-8.05 (m, 2H); 7.85-7.80 (m, 2H); 7.74-7.56 (m, 8H); 7.53-7.49 (m, 6H); 7.34-7.25 (m, 4H); 7.19-7.09 (m, 18H); 7.08-7.00 (m, 22H); 6.99-6.93 (m, 8H); 6.69-6.66 (m, 2H); 6.61-6.56 (m, 4H); 6.47-6.36 (m, 8H); 5.21 (s, 4H); 4.74-4.67 (m, 8H); 4.43-4.30 (m, 12H); 4.20-4.04 (m, 12H); 4.01-3.81 (m, 20H); 3.76-3.56 (m, 12H); 3.40 (q, J = 7.2 Hz, 8H); 3.25-3.23 (m, 4H); 3.20-3.14 (m, 4H); 1.91-1.88 (m, 4H); 1.78-1.71 (m, 4H); 1.46-1.40 (m, 4H); 1.38-1.29 (m, 20H); 1.15 (t, J = 7.2 Hz, 12H).

[0062] 13C NMR (125 MHz, acetone-d6, δ ppm): 168.44, 164.12, 159.96, 159.59, 153.79, 152.99, 152.95, 152.69, 149.66, 149.09, 147.88, 146.53, 146.31, 143.67, 143.62, 142.99, 141.50, 141.25, 140.18, 132.80, 132.12, 131.14, 131.08, 130.71, 130.66, 130.55, 128.99, 128.54, 128.48, 128.29, 127.88, 127.84, 127.76, 126.66, 124.13, 123.87, 123.74, 122.65, 121.10, 114.93, 112.74, 112.10, 111.94, 111.86, 108.75, 101.82, 97.57, 71.92, 71.76, 70.67, 70.45, 70.30, 69.84, 67.92, 64.75, 61.92, 60.16, 52.17, 49.90, 44.13, 43.32, 30.15, 26.26, 25.85, 12.09.

[0063] HRMS (ESI+) [M-2PF6-]2+: calcd. for C196H214N12O302+, 1608.7822; found, 1608.7787.

[0064] Next, compound 24 (500 mg, 0.143 mmol) was dissolved in acetonitrile (MeCN, 10 mL), and iodomethane (CH3I, 10 mL) was added to the solution in a sealed tube, and the mixture was stirred at 45°C for 2 days. After the reaction mixture was cooled to room temperature, excess acetonitrile and iodomethane were removed by vacuum evaporation. The resulting solid was washed several times with diethyl ether (Et2O), then dispersed in acetone (30 mL), and an excess of saturated NH4PF6 solution was added, and the mixture was stirred overnight at room temperature. After removing the reaction solvent, the resulting residue was suspended in deionized water (50 mL), filtered, and washed with water (3 × 50 mL). The resulting precipitate was further washed with diethyl ether and dried in a vacuum oven for 12 hours to finally obtain the target [c2]pyrethroid rotaxane DRT / E as a brown solid (440 mg, 80.4%).

[0065] 1H NMR (500 MHz, acetone-d6, δ ppm): 8.94-8.92 (m, 2H); 7.88-7.86 (m, 2H); 7.83-7.80 (m, 2H); 7.67-7.61 (m, 6H); 7.59-7.54 (m, 8H); 7.52-7.46 (m, 4H); 7.30-7.28 (m, 4H); 7.15-7.09 (m, 18H); 7.07-7.04 (m, 12H); 7.03-6.99 (m, 10H); 6.98-6.93 (m, 8H); 6.89-6.86 (m, 2H); 6.74 (d, J = 9 Hz, 2H); 6.62-6.55 (m, 2H); 6.44-6.35 (m, 2H); 5.62 (s, 4H); 4.78-4.60 (m, 12H); 4.53-4.45 (m, 14H); 4.34-4.22 (m, 10H); 4.18-4.03 (m, 10H); 4.00-3.92 (m, 8H); 3.90-3.81 (m, 8H); 3.69-3.58 (m, 8H); 3.40-3.36 (m, 8H); 3.31-3.18 (m, 4H); 3.17-3.09 (m, 4H); 1.76-1.70 (m, 4H); 1.41-1.34 (m, 4H); 1.30-1.26 (m, 24H); 1.13 (t, J = 7.0 Hz, 12H).

[0066] 13C NMR (125 MHz, acetone-d6, δ ppm): 168.15, 164.11, 158.83, 152.81, 152.76, 152.45, 152.17, 149.72, 146.55, 143.70, 143.65, 143.62, 142.36, 141.53, 141.26, 140.24, 139.68, 133.36, 132.09, 131.11, 131.05, 130.79, 130.71, 130.59, 130.35, 129.95, 129.88, 129.62, 129.50, 129.36, 128.61, 127.90, 127.85, 127.78, 126.67, 124.16, 123.80, 123.68, 123.12, 122.70, 122.34, 121.15, 117.37, 114.90, 112.71, 112.59, 111.94, 102.46, 70.67, 70.47, 70.41, 67.94, 64.69, 64.66, 63.71, 60.04, 59.68, 58.67, 58.59, 54.09, 46.09, 44.09, 43.45, 43.32, 38.37, 25.92, 25.86, 11.97, 8.11.

[0067] HRMS (ESI+) [M-4PF6-]4+: calcd. for C198H220N12O304+, 811.9026; found, 811.9008.

[0068] [c2]-Kiylexicarbonyl tannin DRT / E has a diemine ammonium group located in the inner ring space of the first station portion near the macrocycle. After obtaining the target [c2]-Kiylexicarbonyl tannin DRT / E, the base DBU can be added to deprotonate the diemine ammonium group in the first station portion, replacing it with MTA from the second station portion, which enters the inner ring space of the macrocycle, forming the configuration of [c2]-Kiylexicarbonyl tannin DRT / C. Conversely, if the acid TFA is added to [c2]-Kiylexicarbonyl tannin DRT / C, the configuration of [c2]-Kiylexicarbonyl tannin DRT / C can be restored to that of [c2]-Kiylexicarbonyl tannin DRT / E. [ ] [Experimental Example] [1-3] [:] [[c2]] [Pyrethroid rotaxane] [DT / E] [and] [DT / C] [The synthesis of]

[0069] Figure 2C shows the synthetic pathways for [c2]pyrethroid rotaxanes DT / E and DT / C. In Figure 2C, compound 14 (500 mg, 0.55 mmol) was first dissolved in degassed CHCl3 (30 mL) and stirred at room temperature for 3 hours to generate compound 15. Subsequently, compound 33 (385 mg, 0.84 mmol) and Cu[(CH3CN)4PF6] (310 mg, 0.83 mmol) were added to the solution of compound 15, and the mixture was stirred overnight at room temperature under nitrogen. The reaction mixture was diluted with DCM (30 mL), and 0.1 M Na2EDTA aqueous solution (50 mL) was added and stirred, followed by washing with NH4PF6 aqueous solution (2 × 20 mL) and water. The organic layer was dried over anhydrous Na2SO4 and concentrated under reduced pressure. The crude product was purified by column chromatography (using DCM:MeOH = 50:1) to give compound 34 as a white solid (480 mg, 63.6%).

[0070] 1H NMR (500 MHz, acetonitrile-d3, δ ppm): 7.73 (dd, J = 8.0 Hz, J = 2.0 Hz, 2H); 7.55-7.24 (m, 8H); 7.12-7.02 (m, 14H); 7.01-6.96 (m, 8H); 6.93-6.89 (m, 8H); 6.88-6.83 (m, 6H); 6.82-6.69 (m, 12H); 6.65-6.60 (m, 4H); 6.38 (d, J = 8.0 Hz, 1H); 6.13 (d, J = 2.0 Hz, 1H); 5.01 (dd, J = 10.0 Hz, J = 1.5 Hz, 4H); 4.78-4.55 (m, 8H); 4.38-4.20 (m, 12H); 4.16-3.98 (m, 8H); 3.97-3.85 (m, 16H); 3.82-3.67 (m, 12H); 3.65-3.54 (m, 8H); 3.53-3.32 (m, 8H); 1.81-1.77 (m, 4H); 1.73-1.67 (m, 4H); 1.42-1.36 (m, 4H); 1.31-1.20 (m, 24H).

[0071] 13C NMR (125 MHz, acetonitrile-d3, δ ppm): 159.86, 159.75, 157.68, 156.94, 148.03, 147.84, 146.96, 146.78, 146.37, 146.15, 144.31, 144.24, 143.25, 140.16, 139.83, 136.87, 136.80, 136.21, 132.26, 132.22, 131.04, 131.02, 130.82, 130.76, 128.33, 128.24, 127.79, 127.72, 126.38, 125.13, 125.03, 124.74, 124.13, 123.74, 123.40, 122.82, 121.23, 121.00, 120.85, 114.87, 114.09, 113.99, 113.69, 113.61, 113.52, 112.93, 112.38, 112.24, 112.04, 111.99, 111.93, 71.83, 71.69, 71.30, 71.09, 70.68, 70.55, 70.50, 70.46, 70.30, 69.93, 69.83, 69.68, 69.22, 68.60, 68.04, 67.82, 67.53, 67.43, 67.20, 64.77, 64.74, 61.46, 61.41, 58.28, 58.25, 54.41, 52.09, 51.95, 51.83, 51.59, 51.18, 49.96, 32.17, 32.14, 29.89, 29.21, 29.17, 29.12, 29.05, 28.99, 28.88, 28.84, 28.59, 28.50, 26.44, 26.05, 25.71, 25.68.

[0072] Compound 34 (500 mg, 0.182 mmol) was dissolved in acetonitrile (MeCN, 10 mL), and iodomethane (CH3I, 10 mL) was added to the solution in a sealed tube. The mixture was stirred at 45°C for 2 days. After cooling the reaction mixture to room temperature, excess acetonitrile and iodomethane were removed by vacuum evaporation. The resulting solid was washed several times with diethyl ether (Et2O), then suspended in acetone (30 mL), and an excess of saturated NH4PF6 solution was added. The mixture was stirred overnight at room temperature. After removing the reaction solvent, the resulting residue was added to deionized water (50 mL), filtered, and washed with water (3 × 50 mL). The resulting precipitate was further washed with diethyl ether and dried in a vacuum oven for 12 hours to give [c2]pyrethroid rotaxane DT / E as a white solid (420 mg, 75.3%).

[0073] 1H NMR (500 MHz, acetonitrile-d3, δ ppm): 8.34 (dd, J = 7.5 Hz, J = 1.5 Hz, 2H); 7.61-7.24 (m, 8H); 7.14-7.05 (m, 14H); 7.02-6.97 (m, 10H); 6.96-6.90 (m, 8H); 6.89-6.86 (m, 4H); 6.84-6.79 (m, 6H); 6.78-6.77 (m, 2H); 6.76-6.74 (m, 4H); 6.67-6.61 (m, 4H); 6.40 (d, J = 8.5 Hz, 1H); 6.14 (d, J = 2.0 Hz, 1H); 5.20 (dd, J = 10.5 Hz, J = 1.5 Hz, 4H); 4.79-4.48 (m, 16H); 4.40-4.23 (m, 4H); 4.18 (dd, J = 6.0 Hz, J = 1.5 Hz, 6H); 4.14-4.07 (m, 4H); 4.05-3.88 (m, 16H); 3.84-3.75 (m, 8H); 3.74-3.54 (m, 16H); 3.53-3.34 (m, 8H); 1.88-1.81 (m, 4H); 1.75-1.69 (m, 4H); 1.44-1.38 (m, 4H); 1.36–1.28 (m, 24H).

[0074] 13C NMR (125 MHz, acetonitrile-d3, δ ppm): 159.88, 159.79, 157.77, 157.75, 155.73, 155.69, 148.06, 147.92, 147.87, 147.00, 146.81, 146.41, 146.19, 144.14, 144.09, 144.06, 140.66, 139.81, 139.53, 138.20, 138.23, 136.07, 136.02, 132.49, 132.47, 132.22, 131.02, 130.99, 130.84, 130.77, 129.36, 128.40, 127.88, 127.85, 127.80, 127.76, 126.51, 126.48, 125.13, 125.02, 124.78, 124.18, 123.45, 122.86, 121.23, 121.02, 120.87, 114.86, 114.80, 114.26, 114.21, 114.17, 113.76, 113.65, 113.54, 112.95, 112.41, 112.27, 112.06, 112.01, 111.96, 71.85, 71.71, 71.31, 71.10, 70.69, 70.54, 70.49, 70.34, 70.31, 69.97, 69.86, 69.70, 69.25, 68.63, 68.10, 67.93, 67.81, 67.54, 67.46, 67.28, 67.23, 64.81, 64.78, 58.29, 58.24, 54.41, 54.04, 52.12, 52.00, 51.84, 51.60, 38.45, 32.16, 29.44, 29.23, 29.16, 29.08, 28.99, 28.92, 28.56, 25.79, 25.60.

[0075] HRMS (ESI+) [M-4PF6]4+: calcd. for C150H184N8O244+, 620.5859; found, 620.5842.

[0076] [c2]pyrethroid DT / E has a dimethylammonium group at the first site of the macrocyclic region located within the ring space of the macrocyclic region. After obtaining the target [c2]pyrethroid DT / E, the base DBU can be added to deprotonate the dimethylammonium group at the first site, replacing it with the MTA at the second site, which enters the ring space of the macrocyclic region, forming the configuration of [c2]pyrethroid DT / C. Conversely, if the acid TFA is added to [c2]pyrethroid DT / C, the configuration of [c2]pyrethroid DT / C can be restored to that of [c2]pyrethroid DT / E. [Comparative Example] [1] [Rhodamine derivatives] [ (R2) ] [The synthesis of]

[0077] Figure 3 shows the chemical structure and synthetic route of the dirodamine derivatives (compound 30 or compound R2). Compound 29 (67 mg, 0.3 mmol) and compound 4 (350 mg, 0.75 mmol) were mixed and dissolved in CHCl3 (20 mL), followed by the addition of Cu[(CH3CN)4PF6] (280 mg, 0.75 mmol). The mixture was stirred overnight at room temperature under nitrogen atmosphere. The reaction mixture was diluted with DCM (30 mL), and 0.1 M Na2EDTA aqueous solution (50 mL) was added and stirred, followed by washing with water. The organic layer was collected, dried over anhydrous Na2SO4, and the organic solvent was removed by evaporation under reduced pressure. The crude product was purified by column chromatography (using DCM:MeOH = 50:1) to finally obtain compound 30 (R2) as a pink powder (275 mg, 78.9%).

[0078] 1H NMR (400 MHz, CDCl3, δ ppm): 7.93-7.89 (m, 2H); 7.60 (s, 2H); 7.48-7.43 (m, 4H); 7.05-7.01 (m, 2H); 6.82-6.81 (m, 2H); 6.61-6.60 (m, 4H); 6.48 (d, J = 8.8 Hz, 2H); 6.39 (d, J = 2.4 Hz, 2H); 6.31 (dd, J = 8.8 Hz, J = 2.4 Hz, 2H); 5.20 (s, 4H); 4.35 (t, J = 7.2 Hz, 4H); 4.03 (s, 2H); 3.42 (s, 4H); 3.34 (q, J = 7.2 Hz, 8H); 3.29-3.23 (m, 4H); 1.92-1.88 (m, 4H); 1.37-1.30 (m, 6H); 1.29-1.25 (m, 6H); 1.17 (t, J = 7.2 Hz, 12H).

[0079] 13C NMR (125 MHz, CDCl3, δ ppm): 170.12, 159.36, 152.92, 143.63, 133.05, 130.32, 129.02, 128.62, 123.82, 123.23, 122.71, 112.03, 111.55, 102.00, 65.58, 62.37, 50.56, 44.67, 30.32, 29.79, 29.26, 28.94, 26.50, 12.58. [Polyurethane] [-[c2]] [Purple film of pyrethroid rotaxane]

[0080] Polyurethane (PUR or PU) is a polymer material produced by the reaction of isocyanates and polyols, with its main chain containing carbamate structural units. This polymer material possesses both the elasticity of rubber and the strength and excellent processability of plastics. Therefore, a polyurethane-[C2]pyrethroid rotaxane polymer material can be obtained by polymerizing rhodamine derivatives (or tetraphenylethylene derivatives) with diol groups (-OH), tetraethylene glycol (TEG), and [C2]pyrethroid rotaxane (-OH located on the RH or TPE end cap) and hexamethylene diisocyanate (HDI) with diisocyanate groups (-NCO) as the main chain of polyurethane, and adding triethanolamine (TEA) as a crosslinking agent.

[0081] All PUR films were prepared according to the methods described in previous literature (Z. Wang, Z. Ma, Y. Wang, Z. Xu, Y. Luo, Y. Wei, X. Jia, A Novel Mechanochromic and Photochromic Polymer Film: When Rhodamine Joins Polyurethane, Adv. Mater. 27 (2015) 6469-6474; TM Khang, R. Huang, A. Khan, W.-T. Chuang, PQ Nhien, TTK Cuc, BTB Hue, K.-H. Wei, Y.-K. Li, H.-C. Lin, Reversible Ratiometric Mechanochromic Fluorescence Switching in Highly Stretchable Polyurethane Elastomers with Ultratoughness Enhanced by Polyrotaxane, ACS Materials Lett. 4 (2022) 2537-2546), with some modifications. [Comparative Example] [2-1] [:] [PUR] [Polyurethane] [The synthesis of]

[0082] In this comparative example, without adding any [c2] pyrethroid rotaxane, only a rhodamine derivative (compound 3) with a diol group (diol-) and tetraethylene glycol (TEG) and hexamethylene diisocyanate (HDI) with a diisocyanate group (-NCO) were added to polymerize the polyurethane as the main chain, and triethanolamine (TEA) was added as a crosslinking agent to synthesize PUR polyurethane.

[0083] Compound 3 (21.5 mg, 0.05 mmol), tetraethylene glycol (TEG, 864.3 mg, 4.45 mmol), and dibutyltin dilaurate (DBTDL, 1 drop) were dissolved in anhydrous tetrahydrofuran (THF, 6 mL) and refluxed under nitrogen for 15 minutes. Hexamethylene diisocyanate (HDI, 841 mg, 5.0 mmol) was then added, and the reaction was continued for 1 hour. Next, triethanolamine (TEA, 37.3 mg, 0.25 mmol), a crosslinking agent, was dissolved in anhydrous THF (2 mL) and added to the above mixture, and the reaction was continued for 15 minutes. The resulting solution was then poured into a Teflon mold and dried in a vacuum oven at 70°C for 1 day, finally yielding a transparent straw-colored PUR polyurethane film. Table 1 shows the experimental results of how the mechanical properties of PUR films changed with varying amounts of TEA or compound 3 during the synthesis of PUR films.

[0084] First, the content of TEA crosslinking agent is crucial to the formation and mechanical properties of PUR films. Without the addition of TEA, films cannot be formed, resulting only in powdery substances. With increasing TEA content, the fracture stress and fracture strain generally show a trend of first increasing and then decreasing. The PUR-6 film containing 0.25 mmol TEA exhibits the best mechanical properties, with the highest fracture stress (8.92 MPa) and fracture strain (4153 ± 77%).

[0085] Secondly, the content of compound 3, a rhodamine derivative, also affects the mechanical properties of the PUR film. When the content of compound 3 exceeds 0.05 mmol, the film becomes brittle, and the fracture stress and fracture strain decrease significantly.

[0086] The content of TEG is also crucial to the formation and mechanical properties of PUR films. PUR films cannot be formed without TEG. As the TEG content increases, the fracture stress and fracture strain generally show a trend of first increasing and then decreasing.

[0087] Based on the experimental results of the above mechanical properties, the optimal addition ratio of each monomer and crosslinking agent in Table 1 is currently the addition ratio for PUR-6 film. Furthermore, it can be found that by adjusting the ratio of each monomer and crosslinking agent in the PUR film, its mechanical properties can be optimized.

[0088] Table 1: Relationship between different proportions of TEA and Compound 3 in PUR films and mechanical properties PU samples [Compound] [3] (mmol) [TEG] (mmol) [HDI] (mmol) [TEA] (mmol) Fracture stress (MPa) Fracture strain (%) [*PUR-1] 0.05 4.45 5.0 0 , , [*PUR-2] 0.05 4.45 5.0 0.05 , , [PUR-3] 0.05 4.45 5.0 0.10 5.15 2810 ± 58 [PUR-4] 0.05 4.45 5.0 0.15 > 7.58 > 6000 [PUR-5] 0.05 4.45 5.0 0.20 9.03 5325 ± 113 [PUR-6] 0.05 4.45 5.0 0.25 8.92 4153 ± 77 [PUR-7] 0.05 4.45 5.0 0.30 7.85 3319 ± 67 [PUR-8] 0.05 4.45 5.0 0.35 6.82 742 ± 14 [*PUR-9] 0.05 0 5.0 0.25 -- -- [PUR-10] 0.06 4.45 5.0 0.25 7.39 3775 ± 96 [PUR-11] 0.07 4.45 5.0 0.25 5.88 2690 ± 72 *This is a powder product.

[0089] Figure 5 shows a schematic diagram of the luminescence of the rhodamine derivative monomer under stress, demonstrating its transformation from a non-luminescent closed-ring form to an open-ring form emitting yellow-orange light (i.e., the change of the PUR-6 film before and after stretching). Among the monomers of PUR polyurethane, compound 3 of the rhodamine derivative is a mechanophore. As shown in Figure 5, when compound 3 is polymerized to form PUR polyurethane, the spiropyran structure of the rhodamine derivative monomer changes from a closed-ring structure (5-membered ring on the left side of Figure 5) to an open-ring structure (on the right side of Figure 5) through the ring-opening action of spirolactam, thus forming a chromophore that emits 575 nm yellow-orange fluorescence. Therefore, the intensity of the tensile force borne by the PUR polyurethane material can be measured by the luminescence intensity of the rhodamine derivative monomer. Basically, there is a positive correlation between the luminescence intensity of the rhodamine derivative monomer and the tensile force applied.

[0090] Figure 6 shows the relative photoluminescence (PL) intensity of the yellow-orange light emitted by the PUR-6 film under different strains. Initially, the PUR-6 film exhibits weak blue fluorescence (approximately 440 nm), which is related to the urethane bonds in the PUR-6 film. Then, as shown in Figure 6, as the PUR film is gradually stretched, the ring-opening form of the rhodamine derivative monomer gradually appears, producing yellow-orange fluorescence at 575 nm. Subsequently, continued stretching of the PUR film leads to a continuous increase in the intensity of the yellow-orange fluorescence, indicating that external force can effectively activate the ring-opening reaction of the rhodamine derivative monomer.

[0091] The study of the basic properties of PUR films without the [c2] pyrethroid monomer moiety provides a basis for subsequent comparative studies of PUR films with the [c2] pyrethroid monomer moiety. [Experimental Example] [2-1] [:] [PUR-DR] [Polyurethane]

[0092] Figure 4A shows the synthesis of PUR-DR polyurethane. In this experimental example, the amounts of TEG, HDI, and TEA added during the polymerization reaction were 4.45 mmol, 5.0 mmol, and 0.25 mmol, respectively. The total amount of compound 3 and [c2] pyrethroid DR / E or compound 3 and [c2] pyrethroid DR / C added was 0.05 mmol. By varying the amount of [c2] pyrethroid DR / E or [c2] pyrethroid DR / C added, the experimental results shown in Tables 2 and 3 were obtained.

[0093] Table 2 shows that with the increase of [c2]pyrethroid DR / E content, the fracture stress and fracture strain of the PUR-DR / E film first increase and then decrease. When the [c2]pyrethroid DR / E content is 0.0025 mmol, the PUR-DR / E-2 film exhibits the best mechanical properties, with the highest fracture stress (11.12 MPa) and fracture strain (4585 ± 86%). Compared with the PUR-6 film without [c2]pyrethroid DR / E, the addition of [c2]pyrethroid DR / E improves the mechanical properties of the PUR-DR / E film. This may be because the addition of DR / E enhances the crosslinking density of the polyurethane, and the sliding motion of [c2]pyrethroid DR / E provides an additional energy dissipation mechanism.

[0094] As shown in Table 3, with the increase of [c2]pyrethroid DR / C content, the fracture stress and fracture strain of the PUR-DR / C film showed a trend of first increasing and then decreasing. When the [c2]pyrethroid DR / C content was 0.0025 mmol, the PUR-DR / C-2 film exhibited the best mechanical properties, with the highest fracture stress (11.80 MPa) and fracture strain (5482 ± 115%). Compared with the PUR(s) film without [c2]pyrethroid DR / C, the addition of DR / C significantly improved the mechanical properties of the PUR-DR / C film. This may be because the sliding distance of [c2]pyrethroid DR / C is longer than that of DR / E, thus providing a more effective energy dissipation mechanism during stretching to disperse the mechanical stress borne by the PUR-DR / C film.

[0095] At the same content, the mechanical properties of PUR-DR / C film are superior to those of PUR-DR / E film. Data in Tables 2 and 3 both indicate that introducing [c2]pyrethroid DR / E and DR / C into PUR film can significantly improve its mechanical properties.

[0096] Table 2: Relationship between different proportions of DR / E and mechanical properties in PUR-DR / E films. The addition amounts of TEG, HDI and TEA were 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. PU samples [Compound] [3] (mmol) [DR / E] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.0500 0 8.92 4153 ± 77 [PUR-DR / E-1] 0.0475 0.00125 9.83 4303 ± 91 [PUR-DR / E-2] 0.0450 0.00250 11.12 4585 ± 86 [PUR-DR / E-3] 0.0425 0.00375 11.00 4420 ± 79 [PUR-DR / E-4] 0.0400 0.00500 10.59 4009 ± 82 [PUR-DR / E-5] 0.0375 0.00625 9.54 3529 ± 71 [PUR-DR / E-6] 0.0350 0.00750 8.78 2899 ± 46

[0097] Table 3: Relationship between different proportions of DR / C and mechanical properties in PUR-DR / C films. The addition amounts of TEG, HDI and TEA were 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. PU sample [Compound] [3] (mmol) [DR / E] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.0500 0 8.92 4153 ± 77 [PUR-DR / C-1] 0.0475 0.00125 9.83 4627 ± 101 [PUR-DR / C-2] 0.0450 0.00250 11.80 5482 ± 115 [PUR-DR / C-3] 0.0425 0.00375 10.20 5156 ± 96 [PUR-DR / C-4] 0.0400 0.00500 9.35 4858 ± 107 [PUR-DR / C-5] 0.0375 0.00625 9.28 3619 ± 56 [PUR-DR / C-6] 0.0305 0.00750 8.25 3056 ± 51

[0098] Figure 7 shows the relative photoluminescence (PL) intensity of the yellow-orange light emitted by the PUR-DR / C-2 film under different strains. Similar to the PUR-6 film, in the initial state, the PUR-DR / C-2 film exhibits weak blue fluorescence (approximately 440 nm), which is related to the urethane bonds in the PUR-DR / C-2 film. Then, as the PUR film is gradually stretched, the rhodamine derivative monomer portion begins to emit 575 nm yellow-orange fluorescence, and the intensity of the yellow-orange fluorescence increases continuously with increasing tensile strain, as shown in Figure 7. [Experimental Example] [2-2] [:] [PUR-DRT] [Polyurethane]

[0099] Since [c2]pyrethroid DR and DRT have the same main structure, the only difference being that the macrocyclic portion of [c2]pyrethroid DR has an additional TPE group attached, their synthesis methods are similar. PUR-DRT polyurethane can be obtained by replacing [c2]pyrethroid DR with [c2]pyrethroid DR in Figure 4A. In this experimental example, the amounts of TEG, HDI, and TEA added during the polymerization reaction were 4.45 mmol, 5.0 mmol, and 0.25 mmol, respectively. The total amount of compound 3 and [c2]pyrethroid DR / E or compound 3 and [c2]pyrethroid DR / C added was 0.05 mmol. Varying the amounts of [c2]pyrethroid DR / E or [c2]pyrethroid DR / C yielded the experimental results shown in Tables 4 and 5.

[0100] As shown in Tables 4 and 5, when the addition amounts of [c2]pyrethroid DRT / E or DRT / C are low, their sliding motion can enhance the mechanical properties of the PUR film. However, when the addition amounts of [c2]pyrethroid DRT / E or DRT / C are too high, the large and complex molecular structures of [c2]pyrethroid DRT / E and DRT / C can cause the PUR film to become brittle, thereby reducing its toughness.

[0101] Furthermore, it can be seen that the fracture stress and fracture strain of the PUR films containing DRT / C in Table 5 are higher than those of the corresponding PUR films containing DRT / E in Table 4. This may be because the sliding distance of DRT / C is longer than that of DRT / E, thus allowing for better release of the shrinking polyurethane chains, thereby improving the ductility and toughness of the PUR film. The PUR-DRT / C-2 film exhibits the best fracture stress (11.16 MPa) and fracture strain (5199 ± 102%), with a [c2]pyrethroid rotaxane DRT / C content of 0.0025 mmol, and its mechanical properties are similar to those of the PUR-DR / C-2 film.

[0102] Table 4: Relationship between different proportions of DRT / E and mechanical properties in PUR-DRT / E films. The addition amounts of TEG, HDI and TEA were 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. PU samples [Compound] [3] (mmol) [DRT / E] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.0500 0 8.92 4153 ± 77 [PUR-DRT / E-1] 0.0475 0.00125 9.51 4361 ± 78 [PUR-DRT / E-2] 0.0450 0.00250 9.65 4531 ± 85 [PUR-DRT / E-3] 0.0425 0.00375 9.59 4273 ± 86 [PUR-DRT / E-4] 0.0400 0.00500 9.29 3904 ± 80 [PUR-DRT / E-5] 0.0375 0.00625 8.24 3637 ± 63 [PUR-DRT / E-6] 0.0350 0.00750 8.05 2896 ± 60

[0103] Table 5: Relationship between different proportions of DRT / C and mechanical properties in PUR-DRT / C films. The addition amounts of TEG, HDI and TEA were 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. PU samples [Compound] [3] (mmol) [DR / E] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.0500 0 8.92 4153 ± 77 [PUR-DRT / C-1] 0.0475 0.00125 9.00 4408 ± 98 [PUR-DRT / C-2] 0.0450 0.00250 11.16 5199 ± 102 [PUR-DRT / C-3] 0.0425 0.00375 9.74 4971 ± 85 [PUR-DRT / C-4] 0.0400 0.00500 8.05 4617 ± 102 [PUR-DRT / C-5] 0.0375 0.00625 7.73 3643 ± 74 [PUR-DRT / C-6] 0.0305 0.00750 7.91 2998 ± 58

[0104] In PUR-DRT / C polyurethane, the [c2]-kimchizocarbonyl rotaxane DRT monomer has two fluorescent chromophores: a tetraphenyl derivative moiety (TPE) and a rhodamine derivative moiety (RH). The TPE, attached to the macrocyclic moiety, acts as an energy donor, emitting blue fluorescence at a wavelength of 457 nm. RH serves as the end-capping group of one component of the [c2]-kimchizocarbonyl rotaxane DRT molecule. When RH undergoes ring-opening under stress, the ring-opened RH acts as an energy acceptor, absorbing the blue fluorescence emitted by the TPE. Therefore, when the distance between the TPE and RH is close enough, a Förster resonance energy transfer (FRET) between them allows RH to absorb the blue fluorescence emitted by the TPE and emit yellow-orange fluorescence at a wavelength of 575 nm.

[0105] Therefore, the relative configuration of the two constituent molecules of the [c2]pyrethroid rotaxane DRT monomer moiety affects the distance and orientation between TPE and RH, thus influencing their FRET efficiency and ultimately altering their fluorescence properties. Specifically, when the [c2]pyrethroid rotaxane DRT monomer moiety is in the extended state ( / E), the distance between TPE and RH is greater, resulting in lower FRET efficiency; therefore, TPE exhibits stronger blue fluorescence, while RH shows weaker yellow-orange fluorescence. When the [c2]pyrethroid rotaxane DRT monomer moiety is in the contracted state ( / C), the distance between TPE and RH is closer, resulting in higher FRET efficiency; thus, TPE exhibits weaker blue fluorescence, while RH shows stronger yellow-orange fluorescence.

[0106] Figure 8 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative portion emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative portion emitting yellow-orange fluorescence (λem = 575 nm) in the PUR-DRT / C-2 film under different strains. Figure 9 shows that with increasing tensile strain, the yellow-orange fluorescence of RH gradually increases, while the blue fluorescence of TPE gradually decreases, indicating that a FRET effect does indeed occur between TPE and RH. Based on time-resolved photoluminescence (TRPL) experiments, the energy transfer efficiency between TPE and RH in the PUR-DRT / C-2 film is approximately 26.02%.

[0107] Figure 9A shows the shape memory effect and emission color change of the PUR-DRT / C-2 film during stretching and heating (approximately 100°C). As can be seen from Figure 9A, under ultraviolet light (λex = 365 nm), the stretched PUR-DRT / C-2 film emits a yellow-orange fluorescence. After heating to approximately 100°C, the PUR-DRT / C-2 film almost completely recovers its original shape, and the yellow-orange fluorescence disappears, partially restoring its original blue fluorescence. The PUR-DRT / C-2 film can almost completely recover its original shape after heating. Therefore, the [c2]pyrethroid rotaxane monomer moiety enables the PUR film to have good shape recovery ability, with a recovery rate as high as >90%.

[0108] Figures 9B and 9C show the photoluminescence (PL) spectra and relative PL intensities of the PUR-DRT / C-2 films after stretching to 5000% strain length in water at different temperatures (40, 55, 70, 85, and 100°C), for TPE (λem = 457 nm) emitting blue fluorescence and RH (λem = 575 nm) emitting yellow-orange fluorescence. In Figure 9B, the decay rate of the yellow-orange fluorescence intensity of RH increases with increasing temperature, while the recovery rate of the blue fluorescence intensity of TPE also increases. When heated in water at 100°C, the yellow-orange fluorescence of RH almost completely disappears, while the blue fluorescence of TPE partially recovers. These results indicate that heating can promote the recovery of the original mechanofluorescent radioactivity of the PUR-DRT / C-2 film, and the degree of recovery is related to the heating temperature. The higher the temperature, the faster the recovery.

[0109] Therefore, as shown in Figures 9A-9C, the PUR-DRT / C film exhibits a good shape memory effect, and heating can effectively assist the PUR-DRT / C-2 film in restoring its original shape and original mechanical-fluorescent properties. The linkage between the shape memory effect and fluorescence reaction characteristics of the PUR-DRT / C film suggests that it can be used to develop smart materials.

[0110] To further verify the energy transfer effect of the dual fluorescent chromophores, PUR-DT polyurethane and PUT-DR polyurethane were subsequently prepared. [Experimental Example] [2-3] [:] [PUR-DT] [Polyurethane]

[0111] Figure 4B shows the synthesis of PUR-DT polyurethane. In this experimental example, the amounts of compound 3, TEG, HDI, and TEA added during the polymerization reaction were 0.05 mmol, 4.45 mmol, 5.0 mmol, and 0.25 mmol, respectively. Based on the experience of Experiments 2-1 and 2-2, in this experimental example, the amount of [c2]pyrethroid DT / E or [c2]pyrethroid DT / C added was directly determined to be 0.0025 mmol, and the experimental results shown in Table 6 were obtained.

[0112] As shown in Table 6, the PUR film containing DT / C (PUR-DT / C) exhibits higher fracture stress and fracture strain than the PUR film containing DT / E (PUR-DT / E) and the pure PUR film (PUR-6). The high fracture stress and fracture strain of PUR-DT / C can be attributed to the contractile form of DT / C, which allows the DB24C8 macroring to shuttle between two different recognition sites (DBA and MTA stations). This shuttle motion helps dissipate the mechanical energy applied to the PUR film, thereby improving its toughness. In contrast, DT / E adopts its extended form, in which the DB24C8 macroring is located on the secondary ammonium group of the first site. This configuration restricts the movement of the macroring, resulting in less improvement in mechanical properties compared to PUR-DT / C. Furthermore, all PUR film formulations include compound 3 of the rhodamine derivative to impart mechanofluorescence properties to the PU materials.

[0113] Table 6: Mechanical properties of PUR-DT / E film and PUR-DT / C film, with TEG, HDI and TEA added at amounts of 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. [PU] [sample] [Compound] [3] (mmol) [DT / E] (mmol) [DT / C] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.0500 0 0 8.92 4153 ± 77 [PUR-DT / E] 0.0500 0.0025 0 10.85 4430 ± 83 [PUR-DT / C] 0.0500 0 0.0025 11.23 5775 ± 108

[0114] In PUR-DT polyurethane, rhodamine derivatives and [c2]pyrethroid rotaxane DT are both monomers of PU polyurethane, while TPE is used as the end-capping group for [c2]pyrethroid rotaxane DT. Figure 10 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative moiety emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative moiety emitting yellow-orange fluorescence (λem = 575 nm) in the PUR-DT / C film under different strains. As can be seen from Figure 10, the PUR-DT / C film still exhibits the FRET effect. [Experimental Example] [2-4] [:] [PURT-DR] [Polyurethane]

[0115] Figure 4C shows the synthesis of PURT-DR polyurethane. In this experimental example, in addition to compound 3, a rhodamine derivative, compound 31, a tetraphenylethylene derivative, was added as one of the monomers containing a diol group.

[0116] During the polymerization reaction, the amounts of compound 3, compound 31, TEG, HDI, and TEA added were 0.045 mmol, 0.005 mmol, 4.45 mmol, 5.0 mmol, and 0.25 mmol, respectively. Based on the experience of Experiments 2-1 and 2-2, in this experiment, the amount of [c2]pyrethroid DT / E or [c2]pyrethroid DT / C added was directly determined to be 0.0025 mmol, and the experimental results are shown in Table 7.

[0117] As shown in Table 7, both PUR-DR and PURT-DR films exhibit better mechanical properties when [c2]pyrethroid DR has a C configuration. Compared to PUR-DR films, PURT-DR films with the addition of compound 31 have similar fracture stress and fracture strain.

[0118] Table 7: Comparison of mechanical properties of PUR-DR film and PURT-DR film, with TEG, HDI and TEA added at amounts of 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. [PU] [sample] [Compound] [3] (mmol) [Compound]

[31] (mmol) [DR / E] (mmol) [DR / C] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-DR / E-2] 0.045 0 0.0025 0 11.12 4585 ± 86 [PUR-DR / C-2] 0.045 0 0 0.0025 11.80 5482 ± 115 [PURT-DR / E] 0.045 0.005 0.0025 0 11.28 4486 ± 77 [PURT-DR / C] 0.045 0.005 0 0.0025 11.32 5526 ± 102

[0119] In PURT-DR polyurethane, rhodamine derivatives, tetraphenylethylene derivatives, and [c2]pyrethroid rotaxane DT are all monomers of PU polyurethane, while RH is used as the end-capping group for [c2]pyrethroid rotaxane DR. Figure 11 shows the relative photoluminescence (PL) intensities (λex = 365 nm) of the tetraphenylethylene derivative moiety emitting blue fluorescence (λem = 457 nm) and the rhodamine derivative moiety emitting yellow-orange fluorescence (λem = 575 nm) in the PURT-DR / C film under different strains. Figure 11 shows that the PURT-DR film still exhibits the FRET effect. [Comparative Example] [2-2] [:] [PUR-R2] [Polyurethane]

[0120] In this comparative example, compound R2 (i.e., compound 30) was used to replace [c2]pyrethroid rotaxane in the polymerization reaction. The amounts of TEG, HDI, and TEA added were 4.45 mmol, 5.0 mmol, and 0.25 mmol, respectively. The total amount of compound 3 and compound R2 added was 0.05 mmol. By varying the amount of R2 added, the experimental results shown in Table 8 were obtained.

[0121] As shown in Table 8, regardless of the amount of compound R2 monomer added, the mechanical properties of PUR-R2 film are not significantly different from those of PUR-6 film. Compound R2 serves as a control group for [c2]pyrethroid rotaxane. This result demonstrates that the addition of [c2]pyrethroid rotaxane monomer can significantly improve the mechanical properties of PUR film, while compound R2 monomer, lacking a sliding mechanism, cannot achieve a similar effect in improving the mechanical properties of PUR film.

[0122] Table 8: Mechanical properties of PUR-R2 film, with TEG, HDI and TEA added at amounts of 4.45 mmol, 5.0 mmol and 0.25 mmol, respectively. [PU] [sample] [Compound] [3] (mmol) [Compound] [R2] (mmol) Fracture stress (MPa) Fracture strain (%) [PUR-6] 0.05 0 8.92 4153 ± 77 [PUR-R2] [-1] 0.0475 0.00125 8.83 4426 ± 81 [PUR-R2-2] 0.0450 0.00250 8.83 4697 ± 95 [PUR-R2-3] 0.0425 0.00375 8.58 4818 ± 101 [PUR-R2-4] 0.0400 0.00500 8.61 4543 ± 90 [PUR-R2-5] 0.0375 0.00625 7.96 4345 ± 74 [PUR-R2-6] 0.0350 0.00750 7.62 3796 ± 78

[0123] As can be seen from the above, the embodiments of the present invention have at least the following advantages.

[0124] Introducing [c2]pyrethroids, which possess characteristics such as controllable intramolecular sliding, switchable configuration, and stimulatory response, into the mechanical-fluorescent polyurethane (PU) framework can endow the material with unique mechanical and optical properties.

[0125] PUR films containing [c2] pyrethroids exhibit excellent mechanical strength, high tensile strain, and remarkable toughness. In particular, the contractile configurations of [c2] pyrethroids (DR / C and DRT / C) with long-range sliding motion enhance the toughness of the PUR films to 478 MJ / m3, with an optimal strain exceeding 5000% and a stress value as high as 11 MPa.

[0126] Introducing the dual-luciferase [c2]pyrethroid rotaxane DRT / C into the PUR framework achieved the most efficient ratiometric fluorescence behavior between blue-emitting TPE (λem = 457 nm) and yellow-orange-emitting RH (λem = 575 nm). Through the FRET process, the stretched PUR-DRT / C film exhibited reversible dual fluorescence switching characteristics, with an estimated energy transfer efficiency of 26.02%.

[0127] The designed [c2] pyrethroid PUR film exhibits good shape recovery (approximately >90% of its original shape) and reversible ratiomechanical fluorescence emission changes, recovering upon heating to approximately 100°C. These properties make it a potential application in fields such as soft actuators, intelligent robots, tissue scaffolds, and medical devices.

[0128] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

[0129] 110: Large Ring Section 120: First Station Section 130: Bollard section 140: Second Station Section 150: End cap section L1: First connecting part L2: Second connection section

Claims

1. A compound comprising a plurality of moieties, the moieties comprising, in sequence: a macrocyclic moiety comprising a cyclic polyether moiety; a first site moiety bonded to the macrocyclic moiety, wherein the first site moiety comprises a protonable dimethylene amino group, wherein when the first site moiety enters into the macrocyclic moiety of another compound, the first site moiety forms a plurality of hydrogen bonds with the macrocyclic moiety of the other compound; a linear axis moiety bonded to the first site moiety; a second site moiety bonded to the linear axis moiety, wherein the second site moiety comprises an ammonium group capable of forming an electronic resonance structure, wherein when the second site moiety enters into the macrocyclic moiety of another compound, the second site moiety forms a plurality of hydrogen bonds with the macrocyclic moiety of the other compound, wherein the chemical structural formula of the second site moiety is , , , or ; A sealing end portion is bonded to the second site, wherein the sealing end portion includes a first fluorophore, wherein the first fluorophore includes a rhodamine derivative portion (Formula II) or a tetraphenylethylene derivative portion (Formula III), wherein the rhodamine derivative portion is a mechanotropic fluorophore. Formula II Formula III 2. The compound as claimed in claim 1, wherein the macrocyclic moiety comprises the dibenzo-24-crown-8 moiety.

3. The compound as claimed in claim 1, wherein the macrocyclic portion is further bonded to a second fluorophore, wherein one of the first fluorophore and the second fluorophore can serve as an energy donor for Foster resonance energy transfer, and the other can serve as an energy acceptor.

4. The compound as claimed in claim 3, wherein the first chromophore and the second chromophore each independently comprise a rhodamine derivative moiety (Formula II) or a tetraphenylethylene derivative moiety (Formula III), wherein the rhodamine derivative moiety is a mechanotropic chromophore. Formula II Formula III 5. The compound as claimed in claim 1, wherein the spool portion comprises -(CH2)n-, n=6-16, wherein some of the -(CH2)- can be replaced by -O- or substituted.

6. The compound as claimed in claim 1, wherein the macrocyclic portion and the first site portion further include a first connecting portion comprising -(CH2)n-, n=0-9.

7. The compound as claimed in claim 1, wherein the second site portion and the end cap portion further include a second connecting portion comprising -(CH2)nO-, n=1-10, wherein the -O- portion is connected to the end cap portion.

8. A [c2]pyrethroid toughening agent comprising two compounds as claimed in any one of claims 1-7, wherein the spool portion of one of the compounds passes through the macrocycle portion of the other compound, and vice versa.

9. The [c2] pyrethroid toughening agent as described in claim 8, having one of the following chemical structural formulas: .

10. A stretchable, mechanically induced fluorescent polyurethane elastomer, wherein the monomer of its main chain structure comprises: a [c2] pyrethroid toughening agent as described in claim 8 or 9; and a rhodamine derivative having the chemical structural formula shown in Formula 3 below: .

11. The stretchable, mechanically induced fluorescent polyurethane elastomer as described in claim 10, wherein the monomer of the main chain structure further comprises: tetraethylene glycol; and hexamethylene diisocyanate.

12. The stretchable, mechanically induced fluorescent polyurethane elastomer as described in claim 11, wherein the monomer used in the polymerization reaction further comprises a tetraphenylethylene derivative having the chemical structural formula shown in Formula 31 below: .

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